Gear Ratio

[Joselk1]

Loving driving this 70 ss454 car around town.  It’s more of a highway cruiser I’m finding.  I got the axle off the tube and it’s a 2:56 open. Guess that’s why highway driving at 75-80 Is no problem.  I could sacrifice some high speed for a little more fun around town. I’m torn between a 3.08 or the 3.42.  I’ll add a trutrac the same time.  Any real world experiences from anyone?

Thanks

[MC1of80]

Big Red, Barn Find and my brothers 71 SS454 Monte all have 3.31 gears. Oh and my 71 402 4 speed also. Seem to be a great all around gear. 

[MCfan]

My '70 SS had a 2.56 Posi and was a good cruiser, also.  My '70 402 4 speed has a 3.31 Posi which I believe was an option for the SS that year as well.  It would be a compromise between the 3.08 and 3.42.  How tall are the rear tires you plan on running? You can get away with a bit higher (numerical) ratio if you are running a taller tire like a 275/60-15 that is 28" tall.

[Canuck]

I put 3.07 gears in my 71 SS454 and really enjoy driving it. I used to have 3.73 in it and didn’t like it for the way I use the car. 3.31 would be a good gear as well.

[Joselk1]

I wanted 3.31 but they are very hard to find, same with 3.23….  I’m running a 275/60

 

 

[MC1of80]

You can purchase brand new 3.31 gears now. 

[FrankOC]

https://www.ebay.com/itm/222343310691?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=kM_ZdqTnSxm&sssrc=2349624&ssuid=KUagt9GWSEG&var=&widget_ver=artemis&media=COPY

[riverdogs00]

I installed 3.31's and a tru trac on 70 SS that had the same 2.56 open. I find that its happiest in the 25-65mph range. Mine is more of an intown cruiser rather than the highway. It will certainly run at 70+, but I dont like to buzz it that high for mile after mile. If you intend to run it at highway speeds (55-80) a lot, Id consider staying with what you have or the 3.08's.  I have 235-60-15's, so it a short tire. when its time for new tires, I plan to go taller. My other 454/4sp 70' has 275/60/15's, but its not on the road yet. It took me a few tries and different speedo gears to find the right one after I changed gears.

[Scott S.]

I went from a 2.73 gear in an 8.2" to 3.31 gear in a 12 bolt. 

Gives the tires a better grab when launching out of the lights without smoking the tires.

The 2.74 first gear of a 200r4 plus the 0.67 O.D. makes a nice balance between street and highway as well.

[DragCat]

Just throwing this out there since your going trutrac, might want to consider upgrading axels too. Some here have gone Strange, I'm happy with mine. Cant speak gears but I'm running 355's, but I DONT run on the highway 🤣 My 70 SS had the 256 and a posi, but it was a series 2 so I had to upgrade that also with the new gears. Probably not your concern just adding this so if others run across the thread 

[714024SPEED]

My vote is for the 3:31 gears. I have them in my 71 SS .I have 4:10 gears In our black 71 "Covid" it's very fun around town but not for the highway.